The present invention relates to a key cylinder for selectively locking or unlocking a lock mechanism to lock or unlock a vehicle door panel and to a method for assembling the key cylinder.
A prior art key cylinder, which is fitted in a vehicle door panel, includes a rotor. The rotor is rotated by a key. A rod lever is connected to one end of the rotor. The rod lever is rotated and swung integrally with the rotor. Therefore, the rotation of the rotor, which is caused by the key, is transmitted to the rod lever. The movement of the rod lever selectively locks and unlocks a lock mechanism in accordance with the movement of rod lever.
When the key cylinder is assembled, a plurality of lock plates is attached to the rotor. A dummy key is then inserted in the rotor to prevent the lock plates from falling out of the rotor. Unlike a standard key that depresses the lock plates to allow the rotation of the rotor, the dummy key is a grooveless key that prohibits the rotation of the rotor.
A back spring is arranged in a rotor case. After the dummy key is replaced with an authentic key, the rotor is fitted in the rotor case. That is, the rotor is pushed into the rotor case while rotating the rotor with the authentic key. When the ends of the back spring engage associated engagement portions defined in the rotor, the fitting of the rotor into the rotor case is completed.
There is only one authentic key for each cylinder. Therefore, when the rotor and the rotor case are assembled together, the dummy key must be replaced by the authentic key in each cylinder. This requires the authentic key and the key cylinder to be handled together on an assembly line. Also, the need for the replacement of the dummy key with the authentic key increases the number of the steps of the assembling process.
In the rod lever type key cylinder, the basal end of the rod lever must be connected to the basal end of the rotor with a setscrew, a pin, or some other device that prevents separation of the rod lever from the key cylinder. It is thus difficult to assemble the key cylinder. Additionally, when the key cylinder is fitted in an installation portion (installation hole) of a door panel, the rod lever must be manually supported so that the axis of the rod lever coincides with the axis of the rotor. If the rod lever is not manually supported, the weight of the rod lever causes the rod lever to incline, in accordance with the gravity. Therefore, the key cylinder cannot be fitted in the installation portion of the door panel without manually supporting the rod lever during installation. This decreases the assembling efficiency of the key cylinder.
There is a plate lever type key cylinder, in addition to the rod lever type key cylinder. The plate lever type includes a plate lever, which is fixed to an end of a rotor and is integrally rotated with the rotor. The plate lever is connected by a rod to a lock mechanism, which is arranged in a door panel. A key rotates the rotor. The rotation of the rotor is transmitted to the rod by the plate lever. This shifts the lock mechanism between a locked state and an unlocked state.
The key cylinders include main bodies having substantially the same structure. However, the levers of the plate type cylinder and the rod type cylinder each employ an exclusive rotor and rotor case. Thus, the rotor and rotor case of the plate type cylinder is manufactured separately from those of the rod type cylinder.